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本文以广州市大型超市的鱼、虾、蛤蚌为研究对象,研究其四环素耐药菌的分布及四环素耐药基因的携带情况。采用平板涂布法分离四环素耐药菌并统计菌落数,计数结果在102~106 CFU/g之间,其中鱼肠中四环素耐药菌的数量达106 CFU/g。通过PCR对样本总DNA中四环素耐药基因的携带情况进行检测,发现每个样本均携带多个(3~7个)四环素耐药基因。9种四环素耐药基因中,tet(E)的检出率最高6.3%,其次分别为tet(S)(5.1%),tet(M)(3.1%),tet(C)(1.7%)和tet(G)(0.9%)。Southern杂交试验表明四环素抗性菌株Aeromonas spp.和Escherichia coli携带的耐药基因tet(E)存在于质粒上;在无四环素选择压力下对上述两种菌株进行连续传代,其耐药质粒仍稳定存在于菌株中。本研究表明广州市售鱼、虾、蛤蚌中分离得到的细菌对四环素耐药情况较为严重,应得到相关监管部门以及消费者的足够重视。
In this paper, Guangzhou, a large supermarket fish, shrimp, clams as research object, to study the distribution of tetracycline-resistant bacteria and tetracycline resistance gene carrier situation. Tetracycline-resistant bacteria were isolated by plate coating method and the number of colonies was counted. The counting result was between 102 and 106 CFU / g, of which the number of tetracycline-resistant bacteria in the intestine was 106 CFU / g. The tetracycline resistance genes were detected by PCR in total DNA of the samples and found that each sample carried multiple (3 ~ 7) tetracycline resistance genes. Among the nine tetracycline resistance genes, the highest detection rate of tet (E) was 6.3%, followed by tet (S) 5.1%, tet (M) 3.1%, tet (C) 1.7% tet (G) (0.9%). Southern hybridization showed that the tetracycline-resistant strains tetralone-resistant strains tet (E) were present on the plasmids; in the absence of tetracycline selection, the two strains were continuously passaged, and the resistant plasmids were still stable In the strain. This study shows that Guangzhou municipal fish, shrimp, clams isolated bacteria tetracycline resistance is more serious, should be the relevant regulatory authorities and consumers enough attention.